120v Wall Outlet Wiring

Installing a new outlet is safer than overloading an existing one.

Homes need electrical outlets to power appliances and electronic devices, and even though electrical service panels are capable of supplying 240-volt power, most outlets supply 120 volts. The cable from the panel has three wires. One, which is black, is the hot wire, while the white wire is neutral. The bare ground wire is a safety feature that prevents fires and electrocution from current surges. Outlets have an extra terminal pair that allows you to branch off the circuit to another device, so when you wire a 120-volt outlet, there may be two cables in the box.

1

Turn off the power to the circuit by switching off the breaker that controls it. Test the wires in the outlet box with a voltage tester to make sure they're dead. If there are two pairs of wires, separate the circuit pair from those branching off.

2

Turn on the breaker temporarily and test the wires with a voltage tester to identify the circuit pair when you're wiring a GFCI. It's the pair that gives you a positive voltage reading or makes the light go on. Turn off the breaker again after you've identified the pair.

3

Strip 1/2 inch from the ends of the all the white and black wires in the box with wire strippers. Some outlets have a gauge on the back to help you determine how much bare wire you need.

4

Connect the wires to the outlet in one of two ways. Insert the straight, bare wire ends into the self-clamping holes behind the terminal screws. Or bend the ends of the wires clockwise with pliers to make hooks that will fit over the screws.You then secure them by tightening the screws with a Phillips screwdriver.

5

Connect the circuit wires to one pair of terminals that are opposite each other. If you're wiring a GFCI, you must connect them to the pair that is labeled "Line." Connect the black wire to the brass terminal and the white wire to the silver one. Connect the branch wires to the other terminal pair. On a GFCI, this pair is labeled "Load."

6

Twist the bare or green wires in the box together with pliers, leaving one end longer than the other. Make a hook in the long wire and connect it to the green ground terminal on the outlet. Tighten the ground terminal with a screwdriver.

Things You Will Need

Voltage tester

Wire strippers

Pliers

Phillips screwdriver

Tip

When you make a clockwise hook in a wire and hook it around a terminal screw, tightening the screw tightens the wire onto the screw at the same time.

If there aren't any branch circuits, you'll only find one pair of wires in the box. You can connect them to either terminal pair on a regular outlet, but if it's a GFCI, use the "Line" pair, or the outlet won't work properly.

It's a safe practice to wrap electrical tape around the perimeter of the outlet, covering all the terminal screws, to prevent accidental contact inside the electrical box.